xref: /linux/drivers/i2c/i2c-core-base.c (revision 9d68911233472dc2b336f2cf99521bd684ba6092)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Linux I2C core
4  *
5  * Copyright (C) 1995-99 Simon G. Vogl
6  *   With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>
7  *   Mux support by Rodolfo Giometti <giometti@enneenne.com> and
8  *   Michael Lawnick <michael.lawnick.ext@nsn.com>
9  *
10  * Copyright (C) 2013-2017 Wolfram Sang <wsa@kernel.org>
11  */
12 
13 #define pr_fmt(fmt) "i2c-core: " fmt
14 
15 #include <dt-bindings/i2c/i2c.h>
16 #include <linux/acpi.h>
17 #include <linux/clk/clk-conf.h>
18 #include <linux/completion.h>
19 #include <linux/debugfs.h>
20 #include <linux/delay.h>
21 #include <linux/err.h>
22 #include <linux/errno.h>
23 #include <linux/gpio/consumer.h>
24 #include <linux/i2c.h>
25 #include <linux/i2c-smbus.h>
26 #include <linux/idr.h>
27 #include <linux/init.h>
28 #include <linux/interrupt.h>
29 #include <linux/irqflags.h>
30 #include <linux/jump_label.h>
31 #include <linux/kernel.h>
32 #include <linux/module.h>
33 #include <linux/mutex.h>
34 #include <linux/of_device.h>
35 #include <linux/of.h>
36 #include <linux/of_irq.h>
37 #include <linux/pinctrl/consumer.h>
38 #include <linux/pinctrl/devinfo.h>
39 #include <linux/pm_domain.h>
40 #include <linux/pm_runtime.h>
41 #include <linux/pm_wakeirq.h>
42 #include <linux/property.h>
43 #include <linux/rwsem.h>
44 #include <linux/slab.h>
45 
46 #include "i2c-core.h"
47 
48 #define CREATE_TRACE_POINTS
49 #include <trace/events/i2c.h>
50 
51 #define I2C_ADDR_OFFSET_TEN_BIT	0xa000
52 #define I2C_ADDR_OFFSET_SLAVE	0x1000
53 
54 #define I2C_ADDR_7BITS_MAX	0x77
55 #define I2C_ADDR_7BITS_COUNT	(I2C_ADDR_7BITS_MAX + 1)
56 
57 #define I2C_ADDR_DEVICE_ID	0x7c
58 
59 /*
60  * core_lock protects i2c_adapter_idr, and guarantees that device detection,
61  * deletion of detected devices are serialized
62  */
63 static DEFINE_MUTEX(core_lock);
64 static DEFINE_IDR(i2c_adapter_idr);
65 
66 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
67 
68 static DEFINE_STATIC_KEY_FALSE(i2c_trace_msg_key);
69 static bool is_registered;
70 
71 static struct dentry *i2c_debugfs_root;
72 
i2c_transfer_trace_reg(void)73 int i2c_transfer_trace_reg(void)
74 {
75 	static_branch_inc(&i2c_trace_msg_key);
76 	return 0;
77 }
78 
i2c_transfer_trace_unreg(void)79 void i2c_transfer_trace_unreg(void)
80 {
81 	static_branch_dec(&i2c_trace_msg_key);
82 }
83 
i2c_freq_mode_string(u32 bus_freq_hz)84 const char *i2c_freq_mode_string(u32 bus_freq_hz)
85 {
86 	switch (bus_freq_hz) {
87 	case I2C_MAX_STANDARD_MODE_FREQ:
88 		return "Standard Mode (100 kHz)";
89 	case I2C_MAX_FAST_MODE_FREQ:
90 		return "Fast Mode (400 kHz)";
91 	case I2C_MAX_FAST_MODE_PLUS_FREQ:
92 		return "Fast Mode Plus (1.0 MHz)";
93 	case I2C_MAX_TURBO_MODE_FREQ:
94 		return "Turbo Mode (1.4 MHz)";
95 	case I2C_MAX_HIGH_SPEED_MODE_FREQ:
96 		return "High Speed Mode (3.4 MHz)";
97 	case I2C_MAX_ULTRA_FAST_MODE_FREQ:
98 		return "Ultra Fast Mode (5.0 MHz)";
99 	default:
100 		return "Unknown Mode";
101 	}
102 }
103 EXPORT_SYMBOL_GPL(i2c_freq_mode_string);
104 
i2c_match_id(const struct i2c_device_id * id,const struct i2c_client * client)105 const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
106 						const struct i2c_client *client)
107 {
108 	if (!(id && client))
109 		return NULL;
110 
111 	while (id->name[0]) {
112 		if (strcmp(client->name, id->name) == 0)
113 			return id;
114 		id++;
115 	}
116 	return NULL;
117 }
118 EXPORT_SYMBOL_GPL(i2c_match_id);
119 
i2c_get_match_data(const struct i2c_client * client)120 const void *i2c_get_match_data(const struct i2c_client *client)
121 {
122 	struct i2c_driver *driver = to_i2c_driver(client->dev.driver);
123 	const struct i2c_device_id *match;
124 	const void *data;
125 
126 	data = device_get_match_data(&client->dev);
127 	if (!data) {
128 		match = i2c_match_id(driver->id_table, client);
129 		if (!match)
130 			return NULL;
131 
132 		data = (const void *)match->driver_data;
133 	}
134 
135 	return data;
136 }
137 EXPORT_SYMBOL(i2c_get_match_data);
138 
i2c_device_match(struct device * dev,const struct device_driver * drv)139 static int i2c_device_match(struct device *dev, const struct device_driver *drv)
140 {
141 	struct i2c_client	*client = i2c_verify_client(dev);
142 	const struct i2c_driver	*driver;
143 
144 
145 	/* Attempt an OF style match */
146 	if (i2c_of_match_device(drv->of_match_table, client))
147 		return 1;
148 
149 	/* Then ACPI style match */
150 	if (acpi_driver_match_device(dev, drv))
151 		return 1;
152 
153 	driver = to_i2c_driver(drv);
154 
155 	/* Finally an I2C match */
156 	if (i2c_match_id(driver->id_table, client))
157 		return 1;
158 
159 	return 0;
160 }
161 
i2c_device_uevent(const struct device * dev,struct kobj_uevent_env * env)162 static int i2c_device_uevent(const struct device *dev, struct kobj_uevent_env *env)
163 {
164 	const struct i2c_client *client = to_i2c_client(dev);
165 	int rc;
166 
167 	rc = of_device_uevent_modalias(dev, env);
168 	if (rc != -ENODEV)
169 		return rc;
170 
171 	rc = acpi_device_uevent_modalias(dev, env);
172 	if (rc != -ENODEV)
173 		return rc;
174 
175 	return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
176 }
177 
178 /* i2c bus recovery routines */
get_scl_gpio_value(struct i2c_adapter * adap)179 static int get_scl_gpio_value(struct i2c_adapter *adap)
180 {
181 	return gpiod_get_value_cansleep(adap->bus_recovery_info->scl_gpiod);
182 }
183 
set_scl_gpio_value(struct i2c_adapter * adap,int val)184 static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
185 {
186 	gpiod_set_value_cansleep(adap->bus_recovery_info->scl_gpiod, val);
187 }
188 
get_sda_gpio_value(struct i2c_adapter * adap)189 static int get_sda_gpio_value(struct i2c_adapter *adap)
190 {
191 	return gpiod_get_value_cansleep(adap->bus_recovery_info->sda_gpiod);
192 }
193 
set_sda_gpio_value(struct i2c_adapter * adap,int val)194 static void set_sda_gpio_value(struct i2c_adapter *adap, int val)
195 {
196 	gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val);
197 }
198 
i2c_generic_bus_free(struct i2c_adapter * adap)199 static int i2c_generic_bus_free(struct i2c_adapter *adap)
200 {
201 	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
202 	int ret = -EOPNOTSUPP;
203 
204 	if (bri->get_bus_free)
205 		ret = bri->get_bus_free(adap);
206 	else if (bri->get_sda)
207 		ret = bri->get_sda(adap);
208 
209 	if (ret < 0)
210 		return ret;
211 
212 	return ret ? 0 : -EBUSY;
213 }
214 
215 /*
216  * We are generating clock pulses. ndelay() determines durating of clk pulses.
217  * We will generate clock with rate 100 KHz and so duration of both clock levels
218  * is: delay in ns = (10^6 / 100) / 2
219  */
220 #define RECOVERY_NDELAY		5000
221 #define RECOVERY_CLK_CNT	9
222 
i2c_generic_scl_recovery(struct i2c_adapter * adap)223 int i2c_generic_scl_recovery(struct i2c_adapter *adap)
224 {
225 	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
226 	int i = 0, scl = 1, ret = 0;
227 
228 	if (bri->prepare_recovery)
229 		bri->prepare_recovery(adap);
230 	if (bri->pinctrl)
231 		pinctrl_select_state(bri->pinctrl, bri->pins_gpio);
232 
233 	/*
234 	 * If we can set SDA, we will always create a STOP to ensure additional
235 	 * pulses will do no harm. This is achieved by letting SDA follow SCL
236 	 * half a cycle later. Check the 'incomplete_write_byte' fault injector
237 	 * for details. Note that we must honour tsu:sto, 4us, but lets use 5us
238 	 * here for simplicity.
239 	 */
240 	bri->set_scl(adap, scl);
241 	ndelay(RECOVERY_NDELAY);
242 	if (bri->set_sda)
243 		bri->set_sda(adap, scl);
244 	ndelay(RECOVERY_NDELAY / 2);
245 
246 	/*
247 	 * By this time SCL is high, as we need to give 9 falling-rising edges
248 	 */
249 	while (i++ < RECOVERY_CLK_CNT * 2) {
250 		if (scl) {
251 			/* SCL shouldn't be low here */
252 			if (!bri->get_scl(adap)) {
253 				dev_err(&adap->dev,
254 					"SCL is stuck low, exit recovery\n");
255 				ret = -EBUSY;
256 				break;
257 			}
258 		}
259 
260 		scl = !scl;
261 		bri->set_scl(adap, scl);
262 		/* Creating STOP again, see above */
263 		if (scl)  {
264 			/* Honour minimum tsu:sto */
265 			ndelay(RECOVERY_NDELAY);
266 		} else {
267 			/* Honour minimum tf and thd:dat */
268 			ndelay(RECOVERY_NDELAY / 2);
269 		}
270 		if (bri->set_sda)
271 			bri->set_sda(adap, scl);
272 		ndelay(RECOVERY_NDELAY / 2);
273 
274 		if (scl) {
275 			ret = i2c_generic_bus_free(adap);
276 			if (ret == 0)
277 				break;
278 		}
279 	}
280 
281 	/* If we can't check bus status, assume recovery worked */
282 	if (ret == -EOPNOTSUPP)
283 		ret = 0;
284 
285 	if (bri->unprepare_recovery)
286 		bri->unprepare_recovery(adap);
287 	if (bri->pinctrl)
288 		pinctrl_select_state(bri->pinctrl, bri->pins_default);
289 
290 	return ret;
291 }
292 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
293 
i2c_recover_bus(struct i2c_adapter * adap)294 int i2c_recover_bus(struct i2c_adapter *adap)
295 {
296 	if (!adap->bus_recovery_info)
297 		return -EBUSY;
298 
299 	dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
300 	return adap->bus_recovery_info->recover_bus(adap);
301 }
302 EXPORT_SYMBOL_GPL(i2c_recover_bus);
303 
i2c_gpio_init_pinctrl_recovery(struct i2c_adapter * adap)304 static void i2c_gpio_init_pinctrl_recovery(struct i2c_adapter *adap)
305 {
306 	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
307 	struct device *dev = &adap->dev;
308 	struct pinctrl *p = bri->pinctrl ?: dev_pinctrl(dev->parent);
309 
310 	bri->pinctrl = p;
311 
312 	/*
313 	 * we can't change states without pinctrl, so remove the states if
314 	 * populated
315 	 */
316 	if (!p) {
317 		bri->pins_default = NULL;
318 		bri->pins_gpio = NULL;
319 		return;
320 	}
321 
322 	if (!bri->pins_default) {
323 		bri->pins_default = pinctrl_lookup_state(p,
324 							 PINCTRL_STATE_DEFAULT);
325 		if (IS_ERR(bri->pins_default)) {
326 			dev_dbg(dev, PINCTRL_STATE_DEFAULT " state not found for GPIO recovery\n");
327 			bri->pins_default = NULL;
328 		}
329 	}
330 	if (!bri->pins_gpio) {
331 		bri->pins_gpio = pinctrl_lookup_state(p, "gpio");
332 		if (IS_ERR(bri->pins_gpio))
333 			bri->pins_gpio = pinctrl_lookup_state(p, "recovery");
334 
335 		if (IS_ERR(bri->pins_gpio)) {
336 			dev_dbg(dev, "no gpio or recovery state found for GPIO recovery\n");
337 			bri->pins_gpio = NULL;
338 		}
339 	}
340 
341 	/* for pinctrl state changes, we need all the information */
342 	if (bri->pins_default && bri->pins_gpio) {
343 		dev_info(dev, "using pinctrl states for GPIO recovery");
344 	} else {
345 		bri->pinctrl = NULL;
346 		bri->pins_default = NULL;
347 		bri->pins_gpio = NULL;
348 	}
349 }
350 
i2c_gpio_init_generic_recovery(struct i2c_adapter * adap)351 static int i2c_gpio_init_generic_recovery(struct i2c_adapter *adap)
352 {
353 	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
354 	struct device *dev = &adap->dev;
355 	struct gpio_desc *gpiod;
356 	int ret = 0;
357 
358 	/*
359 	 * don't touch the recovery information if the driver is not using
360 	 * generic SCL recovery
361 	 */
362 	if (bri->recover_bus && bri->recover_bus != i2c_generic_scl_recovery)
363 		return 0;
364 
365 	/*
366 	 * pins might be taken as GPIO, so we should inform pinctrl about
367 	 * this and move the state to GPIO
368 	 */
369 	if (bri->pinctrl)
370 		pinctrl_select_state(bri->pinctrl, bri->pins_gpio);
371 
372 	/*
373 	 * if there is incomplete or no recovery information, see if generic
374 	 * GPIO recovery is available
375 	 */
376 	if (!bri->scl_gpiod) {
377 		gpiod = devm_gpiod_get(dev, "scl", GPIOD_OUT_HIGH_OPEN_DRAIN);
378 		if (PTR_ERR(gpiod) == -EPROBE_DEFER) {
379 			ret  = -EPROBE_DEFER;
380 			goto cleanup_pinctrl_state;
381 		}
382 		if (!IS_ERR(gpiod)) {
383 			bri->scl_gpiod = gpiod;
384 			bri->recover_bus = i2c_generic_scl_recovery;
385 			dev_info(dev, "using generic GPIOs for recovery\n");
386 		}
387 	}
388 
389 	/* SDA GPIOD line is optional, so we care about DEFER only */
390 	if (!bri->sda_gpiod) {
391 		/*
392 		 * We have SCL. Pull SCL low and wait a bit so that SDA glitches
393 		 * have no effect.
394 		 */
395 		gpiod_direction_output(bri->scl_gpiod, 0);
396 		udelay(10);
397 		gpiod = devm_gpiod_get(dev, "sda", GPIOD_IN);
398 
399 		/* Wait a bit in case of a SDA glitch, and then release SCL. */
400 		udelay(10);
401 		gpiod_direction_output(bri->scl_gpiod, 1);
402 
403 		if (PTR_ERR(gpiod) == -EPROBE_DEFER) {
404 			ret = -EPROBE_DEFER;
405 			goto cleanup_pinctrl_state;
406 		}
407 		if (!IS_ERR(gpiod))
408 			bri->sda_gpiod = gpiod;
409 	}
410 
411 cleanup_pinctrl_state:
412 	/* change the state of the pins back to their default state */
413 	if (bri->pinctrl)
414 		pinctrl_select_state(bri->pinctrl, bri->pins_default);
415 
416 	return ret;
417 }
418 
i2c_gpio_init_recovery(struct i2c_adapter * adap)419 static int i2c_gpio_init_recovery(struct i2c_adapter *adap)
420 {
421 	i2c_gpio_init_pinctrl_recovery(adap);
422 	return i2c_gpio_init_generic_recovery(adap);
423 }
424 
i2c_init_recovery(struct i2c_adapter * adap)425 static int i2c_init_recovery(struct i2c_adapter *adap)
426 {
427 	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
428 	bool is_error_level = true;
429 	char *err_str;
430 
431 	if (!bri)
432 		return 0;
433 
434 	if (i2c_gpio_init_recovery(adap) == -EPROBE_DEFER)
435 		return -EPROBE_DEFER;
436 
437 	if (!bri->recover_bus) {
438 		err_str = "no suitable method provided";
439 		is_error_level = false;
440 		goto err;
441 	}
442 
443 	if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) {
444 		bri->get_scl = get_scl_gpio_value;
445 		bri->set_scl = set_scl_gpio_value;
446 		if (bri->sda_gpiod) {
447 			bri->get_sda = get_sda_gpio_value;
448 			/* FIXME: add proper flag instead of '0' once available */
449 			if (gpiod_get_direction(bri->sda_gpiod) == 0)
450 				bri->set_sda = set_sda_gpio_value;
451 		}
452 	} else if (bri->recover_bus == i2c_generic_scl_recovery) {
453 		/* Generic SCL recovery */
454 		if (!bri->set_scl || !bri->get_scl) {
455 			err_str = "no {get|set}_scl() found";
456 			goto err;
457 		}
458 		if (!bri->set_sda && !bri->get_sda) {
459 			err_str = "either get_sda() or set_sda() needed";
460 			goto err;
461 		}
462 	}
463 
464 	return 0;
465  err:
466 	if (is_error_level)
467 		dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
468 	else
469 		dev_dbg(&adap->dev, "Not using recovery: %s\n", err_str);
470 	adap->bus_recovery_info = NULL;
471 
472 	return -EINVAL;
473 }
474 
i2c_smbus_host_notify_to_irq(const struct i2c_client * client)475 static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
476 {
477 	struct i2c_adapter *adap = client->adapter;
478 	unsigned int irq;
479 
480 	if (!adap->host_notify_domain)
481 		return -ENXIO;
482 
483 	if (client->flags & I2C_CLIENT_TEN)
484 		return -EINVAL;
485 
486 	irq = irq_create_mapping(adap->host_notify_domain, client->addr);
487 
488 	return irq > 0 ? irq : -ENXIO;
489 }
490 
i2c_device_probe(struct device * dev)491 static int i2c_device_probe(struct device *dev)
492 {
493 	struct i2c_client	*client = i2c_verify_client(dev);
494 	struct i2c_driver	*driver;
495 	bool do_power_on;
496 	int status;
497 
498 	if (!client)
499 		return 0;
500 
501 	client->irq = client->init_irq;
502 
503 	if (!client->irq) {
504 		int irq = -ENOENT;
505 
506 		if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
507 			dev_dbg(dev, "Using Host Notify IRQ\n");
508 			/* Keep adapter active when Host Notify is required */
509 			pm_runtime_get_sync(&client->adapter->dev);
510 			irq = i2c_smbus_host_notify_to_irq(client);
511 		} else if (dev->of_node) {
512 			irq = of_irq_get_byname(dev->of_node, "irq");
513 			if (irq == -EINVAL || irq == -ENODATA)
514 				irq = of_irq_get(dev->of_node, 0);
515 		} else if (ACPI_COMPANION(dev)) {
516 			bool wake_capable;
517 
518 			irq = i2c_acpi_get_irq(client, &wake_capable);
519 			if (irq > 0 && wake_capable)
520 				client->flags |= I2C_CLIENT_WAKE;
521 		}
522 		if (irq == -EPROBE_DEFER) {
523 			status = irq;
524 			goto put_sync_adapter;
525 		}
526 
527 		if (irq < 0)
528 			irq = 0;
529 
530 		client->irq = irq;
531 	}
532 
533 	driver = to_i2c_driver(dev->driver);
534 
535 	/*
536 	 * An I2C ID table is not mandatory, if and only if, a suitable OF
537 	 * or ACPI ID table is supplied for the probing device.
538 	 */
539 	if (!driver->id_table &&
540 	    !acpi_driver_match_device(dev, dev->driver) &&
541 	    !i2c_of_match_device(dev->driver->of_match_table, client)) {
542 		status = -ENODEV;
543 		goto put_sync_adapter;
544 	}
545 
546 	if (client->flags & I2C_CLIENT_WAKE) {
547 		int wakeirq;
548 
549 		wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
550 		if (wakeirq == -EPROBE_DEFER) {
551 			status = wakeirq;
552 			goto put_sync_adapter;
553 		}
554 
555 		device_init_wakeup(&client->dev, true);
556 
557 		if (wakeirq > 0 && wakeirq != client->irq)
558 			status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
559 		else if (client->irq > 0)
560 			status = dev_pm_set_wake_irq(dev, client->irq);
561 		else
562 			status = 0;
563 
564 		if (status)
565 			dev_warn(&client->dev, "failed to set up wakeup irq\n");
566 	}
567 
568 	dev_dbg(dev, "probe\n");
569 
570 	status = of_clk_set_defaults(dev->of_node, false);
571 	if (status < 0)
572 		goto err_clear_wakeup_irq;
573 
574 	do_power_on = !i2c_acpi_waive_d0_probe(dev);
575 	status = dev_pm_domain_attach(&client->dev, do_power_on);
576 	if (status)
577 		goto err_clear_wakeup_irq;
578 
579 	client->devres_group_id = devres_open_group(&client->dev, NULL,
580 						    GFP_KERNEL);
581 	if (!client->devres_group_id) {
582 		status = -ENOMEM;
583 		goto err_detach_pm_domain;
584 	}
585 
586 	client->debugfs = debugfs_create_dir(dev_name(&client->dev),
587 					     client->adapter->debugfs);
588 
589 	if (driver->probe)
590 		status = driver->probe(client);
591 	else
592 		status = -EINVAL;
593 
594 	/*
595 	 * Note that we are not closing the devres group opened above so
596 	 * even resources that were attached to the device after probe is
597 	 * run are released when i2c_device_remove() is executed. This is
598 	 * needed as some drivers would allocate additional resources,
599 	 * for example when updating firmware.
600 	 */
601 
602 	if (status)
603 		goto err_release_driver_resources;
604 
605 	return 0;
606 
607 err_release_driver_resources:
608 	debugfs_remove_recursive(client->debugfs);
609 	devres_release_group(&client->dev, client->devres_group_id);
610 err_detach_pm_domain:
611 	dev_pm_domain_detach(&client->dev, do_power_on);
612 err_clear_wakeup_irq:
613 	dev_pm_clear_wake_irq(&client->dev);
614 	device_init_wakeup(&client->dev, false);
615 put_sync_adapter:
616 	if (client->flags & I2C_CLIENT_HOST_NOTIFY)
617 		pm_runtime_put_sync(&client->adapter->dev);
618 
619 	return status;
620 }
621 
i2c_device_remove(struct device * dev)622 static void i2c_device_remove(struct device *dev)
623 {
624 	struct i2c_client	*client = to_i2c_client(dev);
625 	struct i2c_driver	*driver;
626 
627 	driver = to_i2c_driver(dev->driver);
628 	if (driver->remove) {
629 		dev_dbg(dev, "remove\n");
630 
631 		driver->remove(client);
632 	}
633 
634 	debugfs_remove_recursive(client->debugfs);
635 
636 	devres_release_group(&client->dev, client->devres_group_id);
637 
638 	dev_pm_domain_detach(&client->dev, true);
639 
640 	dev_pm_clear_wake_irq(&client->dev);
641 	device_init_wakeup(&client->dev, false);
642 
643 	client->irq = 0;
644 	if (client->flags & I2C_CLIENT_HOST_NOTIFY)
645 		pm_runtime_put(&client->adapter->dev);
646 }
647 
i2c_device_shutdown(struct device * dev)648 static void i2c_device_shutdown(struct device *dev)
649 {
650 	struct i2c_client *client = i2c_verify_client(dev);
651 	struct i2c_driver *driver;
652 
653 	if (!client || !dev->driver)
654 		return;
655 	driver = to_i2c_driver(dev->driver);
656 	if (driver->shutdown)
657 		driver->shutdown(client);
658 	else if (client->irq > 0)
659 		disable_irq(client->irq);
660 }
661 
i2c_client_dev_release(struct device * dev)662 static void i2c_client_dev_release(struct device *dev)
663 {
664 	kfree(to_i2c_client(dev));
665 }
666 
667 static ssize_t
name_show(struct device * dev,struct device_attribute * attr,char * buf)668 name_show(struct device *dev, struct device_attribute *attr, char *buf)
669 {
670 	return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
671 		       to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
672 }
673 static DEVICE_ATTR_RO(name);
674 
675 static ssize_t
modalias_show(struct device * dev,struct device_attribute * attr,char * buf)676 modalias_show(struct device *dev, struct device_attribute *attr, char *buf)
677 {
678 	struct i2c_client *client = to_i2c_client(dev);
679 	int len;
680 
681 	len = of_device_modalias(dev, buf, PAGE_SIZE);
682 	if (len != -ENODEV)
683 		return len;
684 
685 	len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
686 	if (len != -ENODEV)
687 		return len;
688 
689 	return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
690 }
691 static DEVICE_ATTR_RO(modalias);
692 
693 static struct attribute *i2c_dev_attrs[] = {
694 	&dev_attr_name.attr,
695 	/* modalias helps coldplug:  modprobe $(cat .../modalias) */
696 	&dev_attr_modalias.attr,
697 	NULL
698 };
699 ATTRIBUTE_GROUPS(i2c_dev);
700 
701 const struct bus_type i2c_bus_type = {
702 	.name		= "i2c",
703 	.match		= i2c_device_match,
704 	.probe		= i2c_device_probe,
705 	.remove		= i2c_device_remove,
706 	.shutdown	= i2c_device_shutdown,
707 };
708 EXPORT_SYMBOL_GPL(i2c_bus_type);
709 
710 const struct device_type i2c_client_type = {
711 	.groups		= i2c_dev_groups,
712 	.uevent		= i2c_device_uevent,
713 	.release	= i2c_client_dev_release,
714 };
715 EXPORT_SYMBOL_GPL(i2c_client_type);
716 
717 
718 /**
719  * i2c_verify_client - return parameter as i2c_client, or NULL
720  * @dev: device, probably from some driver model iterator
721  *
722  * When traversing the driver model tree, perhaps using driver model
723  * iterators like @device_for_each_child(), you can't assume very much
724  * about the nodes you find.  Use this function to avoid oopses caused
725  * by wrongly treating some non-I2C device as an i2c_client.
726  */
i2c_verify_client(struct device * dev)727 struct i2c_client *i2c_verify_client(struct device *dev)
728 {
729 	return (dev->type == &i2c_client_type)
730 			? to_i2c_client(dev)
731 			: NULL;
732 }
733 EXPORT_SYMBOL(i2c_verify_client);
734 
735 
736 /* Return a unique address which takes the flags of the client into account */
i2c_encode_flags_to_addr(struct i2c_client * client)737 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
738 {
739 	unsigned short addr = client->addr;
740 
741 	/* For some client flags, add an arbitrary offset to avoid collisions */
742 	if (client->flags & I2C_CLIENT_TEN)
743 		addr |= I2C_ADDR_OFFSET_TEN_BIT;
744 
745 	if (client->flags & I2C_CLIENT_SLAVE)
746 		addr |= I2C_ADDR_OFFSET_SLAVE;
747 
748 	return addr;
749 }
750 
751 /* This is a permissive address validity check, I2C address map constraints
752  * are purposely not enforced, except for the general call address. */
i2c_check_addr_validity(unsigned int addr,unsigned short flags)753 static int i2c_check_addr_validity(unsigned int addr, unsigned short flags)
754 {
755 	if (flags & I2C_CLIENT_TEN) {
756 		/* 10-bit address, all values are valid */
757 		if (addr > 0x3ff)
758 			return -EINVAL;
759 	} else {
760 		/* 7-bit address, reject the general call address */
761 		if (addr == 0x00 || addr > 0x7f)
762 			return -EINVAL;
763 	}
764 	return 0;
765 }
766 
767 /* And this is a strict address validity check, used when probing. If a
768  * device uses a reserved address, then it shouldn't be probed. 7-bit
769  * addressing is assumed, 10-bit address devices are rare and should be
770  * explicitly enumerated. */
i2c_check_7bit_addr_validity_strict(unsigned short addr)771 int i2c_check_7bit_addr_validity_strict(unsigned short addr)
772 {
773 	/*
774 	 * Reserved addresses per I2C specification:
775 	 *  0x00       General call address / START byte
776 	 *  0x01       CBUS address
777 	 *  0x02       Reserved for different bus format
778 	 *  0x03       Reserved for future purposes
779 	 *  0x04-0x07  Hs-mode master code
780 	 *  0x78-0x7b  10-bit slave addressing
781 	 *  0x7c-0x7f  Reserved for future purposes
782 	 */
783 	if (addr < 0x08 || addr > 0x77)
784 		return -EINVAL;
785 	return 0;
786 }
787 
__i2c_check_addr_busy(struct device * dev,void * addrp)788 static int __i2c_check_addr_busy(struct device *dev, void *addrp)
789 {
790 	struct i2c_client	*client = i2c_verify_client(dev);
791 	int			addr = *(int *)addrp;
792 
793 	if (client && i2c_encode_flags_to_addr(client) == addr)
794 		return -EBUSY;
795 	return 0;
796 }
797 
798 /* walk up mux tree */
i2c_check_mux_parents(struct i2c_adapter * adapter,int addr)799 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
800 {
801 	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
802 	int result;
803 
804 	result = device_for_each_child(&adapter->dev, &addr,
805 					__i2c_check_addr_busy);
806 
807 	if (!result && parent)
808 		result = i2c_check_mux_parents(parent, addr);
809 
810 	return result;
811 }
812 
813 /* recurse down mux tree */
i2c_check_mux_children(struct device * dev,void * addrp)814 static int i2c_check_mux_children(struct device *dev, void *addrp)
815 {
816 	int result;
817 
818 	if (dev->type == &i2c_adapter_type)
819 		result = device_for_each_child(dev, addrp,
820 						i2c_check_mux_children);
821 	else
822 		result = __i2c_check_addr_busy(dev, addrp);
823 
824 	return result;
825 }
826 
i2c_check_addr_busy(struct i2c_adapter * adapter,int addr)827 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
828 {
829 	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
830 	int result = 0;
831 
832 	if (parent)
833 		result = i2c_check_mux_parents(parent, addr);
834 
835 	if (!result)
836 		result = device_for_each_child(&adapter->dev, &addr,
837 						i2c_check_mux_children);
838 
839 	return result;
840 }
841 
842 /**
843  * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
844  * @adapter: Target I2C bus segment
845  * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
846  *	locks only this branch in the adapter tree
847  */
i2c_adapter_lock_bus(struct i2c_adapter * adapter,unsigned int flags)848 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
849 				 unsigned int flags)
850 {
851 	rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter));
852 }
853 
854 /**
855  * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
856  * @adapter: Target I2C bus segment
857  * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
858  *	trylocks only this branch in the adapter tree
859  */
i2c_adapter_trylock_bus(struct i2c_adapter * adapter,unsigned int flags)860 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
861 				   unsigned int flags)
862 {
863 	return rt_mutex_trylock(&adapter->bus_lock);
864 }
865 
866 /**
867  * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
868  * @adapter: Target I2C bus segment
869  * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
870  *	unlocks only this branch in the adapter tree
871  */
i2c_adapter_unlock_bus(struct i2c_adapter * adapter,unsigned int flags)872 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
873 				   unsigned int flags)
874 {
875 	rt_mutex_unlock(&adapter->bus_lock);
876 }
877 
i2c_dev_set_name(struct i2c_adapter * adap,struct i2c_client * client,struct i2c_board_info const * info)878 static void i2c_dev_set_name(struct i2c_adapter *adap,
879 			     struct i2c_client *client,
880 			     struct i2c_board_info const *info)
881 {
882 	struct acpi_device *adev = ACPI_COMPANION(&client->dev);
883 
884 	if (info && info->dev_name) {
885 		dev_set_name(&client->dev, "i2c-%s", info->dev_name);
886 		return;
887 	}
888 
889 	if (adev) {
890 		dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
891 		return;
892 	}
893 
894 	dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
895 		     i2c_encode_flags_to_addr(client));
896 }
897 
i2c_dev_irq_from_resources(const struct resource * resources,unsigned int num_resources)898 int i2c_dev_irq_from_resources(const struct resource *resources,
899 			       unsigned int num_resources)
900 {
901 	struct irq_data *irqd;
902 	int i;
903 
904 	for (i = 0; i < num_resources; i++) {
905 		const struct resource *r = &resources[i];
906 
907 		if (resource_type(r) != IORESOURCE_IRQ)
908 			continue;
909 
910 		if (r->flags & IORESOURCE_BITS) {
911 			irqd = irq_get_irq_data(r->start);
912 			if (!irqd)
913 				break;
914 
915 			irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
916 		}
917 
918 		return r->start;
919 	}
920 
921 	return 0;
922 }
923 
924 /*
925  * Serialize device instantiation in case it can be instantiated explicitly
926  * and by auto-detection
927  */
i2c_lock_addr(struct i2c_adapter * adap,unsigned short addr,unsigned short flags)928 static int i2c_lock_addr(struct i2c_adapter *adap, unsigned short addr,
929 			 unsigned short flags)
930 {
931 	if (!(flags & I2C_CLIENT_TEN) &&
932 	    test_and_set_bit(addr, adap->addrs_in_instantiation))
933 		return -EBUSY;
934 
935 	return 0;
936 }
937 
i2c_unlock_addr(struct i2c_adapter * adap,unsigned short addr,unsigned short flags)938 static void i2c_unlock_addr(struct i2c_adapter *adap, unsigned short addr,
939 			    unsigned short flags)
940 {
941 	if (!(flags & I2C_CLIENT_TEN))
942 		clear_bit(addr, adap->addrs_in_instantiation);
943 }
944 
945 /**
946  * i2c_new_client_device - instantiate an i2c device
947  * @adap: the adapter managing the device
948  * @info: describes one I2C device; bus_num is ignored
949  * Context: can sleep
950  *
951  * Create an i2c device. Binding is handled through driver model
952  * probe()/remove() methods.  A driver may be bound to this device when we
953  * return from this function, or any later moment (e.g. maybe hotplugging will
954  * load the driver module).  This call is not appropriate for use by mainboard
955  * initialization logic, which usually runs during an arch_initcall() long
956  * before any i2c_adapter could exist.
957  *
958  * This returns the new i2c client, which may be saved for later use with
959  * i2c_unregister_device(); or an ERR_PTR to describe the error.
960  */
961 struct i2c_client *
i2c_new_client_device(struct i2c_adapter * adap,struct i2c_board_info const * info)962 i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
963 {
964 	struct i2c_client *client;
965 	bool need_put = false;
966 	int status;
967 
968 	client = kzalloc(sizeof *client, GFP_KERNEL);
969 	if (!client)
970 		return ERR_PTR(-ENOMEM);
971 
972 	client->adapter = adap;
973 
974 	client->dev.platform_data = info->platform_data;
975 	client->flags = info->flags;
976 	client->addr = info->addr;
977 
978 	client->init_irq = info->irq;
979 	if (!client->init_irq)
980 		client->init_irq = i2c_dev_irq_from_resources(info->resources,
981 							 info->num_resources);
982 
983 	strscpy(client->name, info->type, sizeof(client->name));
984 
985 	status = i2c_check_addr_validity(client->addr, client->flags);
986 	if (status) {
987 		dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
988 			client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
989 		goto out_err_silent;
990 	}
991 
992 	status = i2c_lock_addr(adap, client->addr, client->flags);
993 	if (status)
994 		goto out_err_silent;
995 
996 	/* Check for address business */
997 	status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
998 	if (status)
999 		goto out_err;
1000 
1001 	client->dev.parent = &client->adapter->dev;
1002 	client->dev.bus = &i2c_bus_type;
1003 	client->dev.type = &i2c_client_type;
1004 	client->dev.of_node = of_node_get(info->of_node);
1005 	client->dev.fwnode = info->fwnode;
1006 
1007 	device_enable_async_suspend(&client->dev);
1008 
1009 	if (info->swnode) {
1010 		status = device_add_software_node(&client->dev, info->swnode);
1011 		if (status) {
1012 			dev_err(&adap->dev,
1013 				"Failed to add software node to client %s: %d\n",
1014 				client->name, status);
1015 			goto out_err_put_of_node;
1016 		}
1017 	}
1018 
1019 	i2c_dev_set_name(adap, client, info);
1020 	status = device_register(&client->dev);
1021 	if (status)
1022 		goto out_remove_swnode;
1023 
1024 	dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
1025 		client->name, dev_name(&client->dev));
1026 
1027 	i2c_unlock_addr(adap, client->addr, client->flags);
1028 
1029 	return client;
1030 
1031 out_remove_swnode:
1032 	device_remove_software_node(&client->dev);
1033 	need_put = true;
1034 out_err_put_of_node:
1035 	of_node_put(info->of_node);
1036 out_err:
1037 	dev_err(&adap->dev,
1038 		"Failed to register i2c client %s at 0x%02x (%d)\n",
1039 		client->name, client->addr, status);
1040 	i2c_unlock_addr(adap, client->addr, client->flags);
1041 out_err_silent:
1042 	if (need_put)
1043 		put_device(&client->dev);
1044 	else
1045 		kfree(client);
1046 	return ERR_PTR(status);
1047 }
1048 EXPORT_SYMBOL_GPL(i2c_new_client_device);
1049 
1050 /**
1051  * i2c_unregister_device - reverse effect of i2c_new_*_device()
1052  * @client: value returned from i2c_new_*_device()
1053  * Context: can sleep
1054  */
i2c_unregister_device(struct i2c_client * client)1055 void i2c_unregister_device(struct i2c_client *client)
1056 {
1057 	if (IS_ERR_OR_NULL(client))
1058 		return;
1059 
1060 	if (client->dev.of_node) {
1061 		of_node_clear_flag(client->dev.of_node, OF_POPULATED);
1062 		of_node_put(client->dev.of_node);
1063 	}
1064 
1065 	if (ACPI_COMPANION(&client->dev))
1066 		acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
1067 
1068 	device_remove_software_node(&client->dev);
1069 	device_unregister(&client->dev);
1070 }
1071 EXPORT_SYMBOL_GPL(i2c_unregister_device);
1072 
1073 /**
1074  * i2c_find_device_by_fwnode() - find an i2c_client for the fwnode
1075  * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_client
1076  *
1077  * Look up and return the &struct i2c_client corresponding to the @fwnode.
1078  * If no client can be found, or @fwnode is NULL, this returns NULL.
1079  *
1080  * The user must call put_device(&client->dev) once done with the i2c client.
1081  */
i2c_find_device_by_fwnode(struct fwnode_handle * fwnode)1082 struct i2c_client *i2c_find_device_by_fwnode(struct fwnode_handle *fwnode)
1083 {
1084 	struct i2c_client *client;
1085 	struct device *dev;
1086 
1087 	if (!fwnode)
1088 		return NULL;
1089 
1090 	dev = bus_find_device_by_fwnode(&i2c_bus_type, fwnode);
1091 	if (!dev)
1092 		return NULL;
1093 
1094 	client = i2c_verify_client(dev);
1095 	if (!client)
1096 		put_device(dev);
1097 
1098 	return client;
1099 }
1100 EXPORT_SYMBOL(i2c_find_device_by_fwnode);
1101 
1102 
1103 static const struct i2c_device_id dummy_id[] = {
1104 	{ "dummy", },
1105 	{ "smbus_host_notify", },
1106 	{ }
1107 };
1108 
dummy_probe(struct i2c_client * client)1109 static int dummy_probe(struct i2c_client *client)
1110 {
1111 	return 0;
1112 }
1113 
1114 static struct i2c_driver dummy_driver = {
1115 	.driver.name	= "dummy",
1116 	.probe		= dummy_probe,
1117 	.id_table	= dummy_id,
1118 };
1119 
1120 /**
1121  * i2c_new_dummy_device - return a new i2c device bound to a dummy driver
1122  * @adapter: the adapter managing the device
1123  * @address: seven bit address to be used
1124  * Context: can sleep
1125  *
1126  * This returns an I2C client bound to the "dummy" driver, intended for use
1127  * with devices that consume multiple addresses.  Examples of such chips
1128  * include various EEPROMS (like 24c04 and 24c08 models).
1129  *
1130  * These dummy devices have two main uses.  First, most I2C and SMBus calls
1131  * except i2c_transfer() need a client handle; the dummy will be that handle.
1132  * And second, this prevents the specified address from being bound to a
1133  * different driver.
1134  *
1135  * This returns the new i2c client, which should be saved for later use with
1136  * i2c_unregister_device(); or an ERR_PTR to describe the error.
1137  */
i2c_new_dummy_device(struct i2c_adapter * adapter,u16 address)1138 struct i2c_client *i2c_new_dummy_device(struct i2c_adapter *adapter, u16 address)
1139 {
1140 	struct i2c_board_info info = {
1141 		I2C_BOARD_INFO("dummy", address),
1142 	};
1143 
1144 	return i2c_new_client_device(adapter, &info);
1145 }
1146 EXPORT_SYMBOL_GPL(i2c_new_dummy_device);
1147 
devm_i2c_release_dummy(void * client)1148 static void devm_i2c_release_dummy(void *client)
1149 {
1150 	i2c_unregister_device(client);
1151 }
1152 
1153 /**
1154  * devm_i2c_new_dummy_device - return a new i2c device bound to a dummy driver
1155  * @dev: device the managed resource is bound to
1156  * @adapter: the adapter managing the device
1157  * @address: seven bit address to be used
1158  * Context: can sleep
1159  *
1160  * This is the device-managed version of @i2c_new_dummy_device. It returns the
1161  * new i2c client or an ERR_PTR in case of an error.
1162  */
devm_i2c_new_dummy_device(struct device * dev,struct i2c_adapter * adapter,u16 address)1163 struct i2c_client *devm_i2c_new_dummy_device(struct device *dev,
1164 					     struct i2c_adapter *adapter,
1165 					     u16 address)
1166 {
1167 	struct i2c_client *client;
1168 	int ret;
1169 
1170 	client = i2c_new_dummy_device(adapter, address);
1171 	if (IS_ERR(client))
1172 		return client;
1173 
1174 	ret = devm_add_action_or_reset(dev, devm_i2c_release_dummy, client);
1175 	if (ret)
1176 		return ERR_PTR(ret);
1177 
1178 	return client;
1179 }
1180 EXPORT_SYMBOL_GPL(devm_i2c_new_dummy_device);
1181 
1182 /**
1183  * i2c_new_ancillary_device - Helper to get the instantiated secondary address
1184  * and create the associated device
1185  * @client: Handle to the primary client
1186  * @name: Handle to specify which secondary address to get
1187  * @default_addr: Used as a fallback if no secondary address was specified
1188  * Context: can sleep
1189  *
1190  * I2C clients can be composed of multiple I2C slaves bound together in a single
1191  * component. The I2C client driver then binds to the master I2C slave and needs
1192  * to create I2C dummy clients to communicate with all the other slaves.
1193  *
1194  * This function creates and returns an I2C dummy client whose I2C address is
1195  * retrieved from the platform firmware based on the given slave name. If no
1196  * address is specified by the firmware default_addr is used.
1197  *
1198  * On DT-based platforms the address is retrieved from the "reg" property entry
1199  * cell whose "reg-names" value matches the slave name.
1200  *
1201  * This returns the new i2c client, which should be saved for later use with
1202  * i2c_unregister_device(); or an ERR_PTR to describe the error.
1203  */
i2c_new_ancillary_device(struct i2c_client * client,const char * name,u16 default_addr)1204 struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client,
1205 						const char *name,
1206 						u16 default_addr)
1207 {
1208 	struct device_node *np = client->dev.of_node;
1209 	u32 addr = default_addr;
1210 	int i;
1211 
1212 	if (np) {
1213 		i = of_property_match_string(np, "reg-names", name);
1214 		if (i >= 0)
1215 			of_property_read_u32_index(np, "reg", i, &addr);
1216 	}
1217 
1218 	dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
1219 	return i2c_new_dummy_device(client->adapter, addr);
1220 }
1221 EXPORT_SYMBOL_GPL(i2c_new_ancillary_device);
1222 
1223 /* ------------------------------------------------------------------------- */
1224 
1225 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
1226 
i2c_adapter_dev_release(struct device * dev)1227 static void i2c_adapter_dev_release(struct device *dev)
1228 {
1229 	struct i2c_adapter *adap = to_i2c_adapter(dev);
1230 	complete(&adap->dev_released);
1231 }
1232 
i2c_adapter_depth(struct i2c_adapter * adapter)1233 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
1234 {
1235 	unsigned int depth = 0;
1236 	struct device *parent;
1237 
1238 	for (parent = adapter->dev.parent; parent; parent = parent->parent)
1239 		if (parent->type == &i2c_adapter_type)
1240 			depth++;
1241 
1242 	WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
1243 		  "adapter depth exceeds lockdep subclass limit\n");
1244 
1245 	return depth;
1246 }
1247 EXPORT_SYMBOL_GPL(i2c_adapter_depth);
1248 
1249 /*
1250  * Let users instantiate I2C devices through sysfs. This can be used when
1251  * platform initialization code doesn't contain the proper data for
1252  * whatever reason. Also useful for drivers that do device detection and
1253  * detection fails, either because the device uses an unexpected address,
1254  * or this is a compatible device with different ID register values.
1255  *
1256  * Parameter checking may look overzealous, but we really don't want
1257  * the user to provide incorrect parameters.
1258  */
1259 static ssize_t
new_device_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)1260 new_device_store(struct device *dev, struct device_attribute *attr,
1261 		 const char *buf, size_t count)
1262 {
1263 	struct i2c_adapter *adap = to_i2c_adapter(dev);
1264 	struct i2c_board_info info;
1265 	struct i2c_client *client;
1266 	char *blank, end;
1267 	int res;
1268 
1269 	memset(&info, 0, sizeof(struct i2c_board_info));
1270 
1271 	blank = strchr(buf, ' ');
1272 	if (!blank) {
1273 		dev_err(dev, "%s: Missing parameters\n", "new_device");
1274 		return -EINVAL;
1275 	}
1276 	if (blank - buf > I2C_NAME_SIZE - 1) {
1277 		dev_err(dev, "%s: Invalid device name\n", "new_device");
1278 		return -EINVAL;
1279 	}
1280 	memcpy(info.type, buf, blank - buf);
1281 
1282 	/* Parse remaining parameters, reject extra parameters */
1283 	res = sscanf(++blank, "%hi%c", &info.addr, &end);
1284 	if (res < 1) {
1285 		dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
1286 		return -EINVAL;
1287 	}
1288 	if (res > 1  && end != '\n') {
1289 		dev_err(dev, "%s: Extra parameters\n", "new_device");
1290 		return -EINVAL;
1291 	}
1292 
1293 	if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
1294 		info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
1295 		info.flags |= I2C_CLIENT_TEN;
1296 	}
1297 
1298 	if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
1299 		info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
1300 		info.flags |= I2C_CLIENT_SLAVE;
1301 	}
1302 
1303 	client = i2c_new_client_device(adap, &info);
1304 	if (IS_ERR(client))
1305 		return PTR_ERR(client);
1306 
1307 	/* Keep track of the added device */
1308 	mutex_lock(&adap->userspace_clients_lock);
1309 	list_add_tail(&client->detected, &adap->userspace_clients);
1310 	mutex_unlock(&adap->userspace_clients_lock);
1311 	dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1312 		 info.type, info.addr);
1313 
1314 	return count;
1315 }
1316 static DEVICE_ATTR_WO(new_device);
1317 
1318 /*
1319  * And of course let the users delete the devices they instantiated, if
1320  * they got it wrong. This interface can only be used to delete devices
1321  * instantiated by i2c_sysfs_new_device above. This guarantees that we
1322  * don't delete devices to which some kernel code still has references.
1323  *
1324  * Parameter checking may look overzealous, but we really don't want
1325  * the user to delete the wrong device.
1326  */
1327 static ssize_t
delete_device_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)1328 delete_device_store(struct device *dev, struct device_attribute *attr,
1329 		    const char *buf, size_t count)
1330 {
1331 	struct i2c_adapter *adap = to_i2c_adapter(dev);
1332 	struct i2c_client *client, *next;
1333 	unsigned short addr;
1334 	char end;
1335 	int res;
1336 
1337 	/* Parse parameters, reject extra parameters */
1338 	res = sscanf(buf, "%hi%c", &addr, &end);
1339 	if (res < 1) {
1340 		dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1341 		return -EINVAL;
1342 	}
1343 	if (res > 1  && end != '\n') {
1344 		dev_err(dev, "%s: Extra parameters\n", "delete_device");
1345 		return -EINVAL;
1346 	}
1347 
1348 	/* Make sure the device was added through sysfs */
1349 	res = -ENOENT;
1350 	mutex_lock_nested(&adap->userspace_clients_lock,
1351 			  i2c_adapter_depth(adap));
1352 	list_for_each_entry_safe(client, next, &adap->userspace_clients,
1353 				 detected) {
1354 		if (i2c_encode_flags_to_addr(client) == addr) {
1355 			dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1356 				 "delete_device", client->name, client->addr);
1357 
1358 			list_del(&client->detected);
1359 			i2c_unregister_device(client);
1360 			res = count;
1361 			break;
1362 		}
1363 	}
1364 	mutex_unlock(&adap->userspace_clients_lock);
1365 
1366 	if (res < 0)
1367 		dev_err(dev, "%s: Can't find device in list\n",
1368 			"delete_device");
1369 	return res;
1370 }
1371 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1372 				  delete_device_store);
1373 
1374 static struct attribute *i2c_adapter_attrs[] = {
1375 	&dev_attr_name.attr,
1376 	&dev_attr_new_device.attr,
1377 	&dev_attr_delete_device.attr,
1378 	NULL
1379 };
1380 ATTRIBUTE_GROUPS(i2c_adapter);
1381 
1382 const struct device_type i2c_adapter_type = {
1383 	.groups		= i2c_adapter_groups,
1384 	.release	= i2c_adapter_dev_release,
1385 };
1386 EXPORT_SYMBOL_GPL(i2c_adapter_type);
1387 
1388 /**
1389  * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1390  * @dev: device, probably from some driver model iterator
1391  *
1392  * When traversing the driver model tree, perhaps using driver model
1393  * iterators like @device_for_each_child(), you can't assume very much
1394  * about the nodes you find.  Use this function to avoid oopses caused
1395  * by wrongly treating some non-I2C device as an i2c_adapter.
1396  */
i2c_verify_adapter(struct device * dev)1397 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1398 {
1399 	return (dev->type == &i2c_adapter_type)
1400 			? to_i2c_adapter(dev)
1401 			: NULL;
1402 }
1403 EXPORT_SYMBOL(i2c_verify_adapter);
1404 
i2c_scan_static_board_info(struct i2c_adapter * adapter)1405 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1406 {
1407 	struct i2c_devinfo	*devinfo;
1408 
1409 	down_read(&__i2c_board_lock);
1410 	list_for_each_entry(devinfo, &__i2c_board_list, list) {
1411 		if (devinfo->busnum == adapter->nr &&
1412 		    IS_ERR(i2c_new_client_device(adapter, &devinfo->board_info)))
1413 			dev_err(&adapter->dev,
1414 				"Can't create device at 0x%02x\n",
1415 				devinfo->board_info.addr);
1416 	}
1417 	up_read(&__i2c_board_lock);
1418 }
1419 
i2c_do_add_adapter(struct i2c_driver * driver,struct i2c_adapter * adap)1420 static int i2c_do_add_adapter(struct i2c_driver *driver,
1421 			      struct i2c_adapter *adap)
1422 {
1423 	/* Detect supported devices on that bus, and instantiate them */
1424 	i2c_detect(adap, driver);
1425 
1426 	return 0;
1427 }
1428 
__process_new_adapter(struct device_driver * d,void * data)1429 static int __process_new_adapter(struct device_driver *d, void *data)
1430 {
1431 	return i2c_do_add_adapter(to_i2c_driver(d), data);
1432 }
1433 
1434 static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1435 	.lock_bus =    i2c_adapter_lock_bus,
1436 	.trylock_bus = i2c_adapter_trylock_bus,
1437 	.unlock_bus =  i2c_adapter_unlock_bus,
1438 };
1439 
i2c_host_notify_irq_teardown(struct i2c_adapter * adap)1440 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1441 {
1442 	struct irq_domain *domain = adap->host_notify_domain;
1443 	irq_hw_number_t hwirq;
1444 
1445 	if (!domain)
1446 		return;
1447 
1448 	for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1449 		irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1450 
1451 	irq_domain_remove(domain);
1452 	adap->host_notify_domain = NULL;
1453 }
1454 
i2c_host_notify_irq_map(struct irq_domain * h,unsigned int virq,irq_hw_number_t hw_irq_num)1455 static int i2c_host_notify_irq_map(struct irq_domain *h,
1456 					  unsigned int virq,
1457 					  irq_hw_number_t hw_irq_num)
1458 {
1459 	irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1460 
1461 	return 0;
1462 }
1463 
1464 static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1465 	.map = i2c_host_notify_irq_map,
1466 };
1467 
i2c_setup_host_notify_irq_domain(struct i2c_adapter * adap)1468 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1469 {
1470 	struct irq_domain *domain;
1471 
1472 	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1473 		return 0;
1474 
1475 	domain = irq_domain_create_linear(adap->dev.parent->fwnode,
1476 					  I2C_ADDR_7BITS_COUNT,
1477 					  &i2c_host_notify_irq_ops, adap);
1478 	if (!domain)
1479 		return -ENOMEM;
1480 
1481 	adap->host_notify_domain = domain;
1482 
1483 	return 0;
1484 }
1485 
1486 /**
1487  * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1488  * I2C client.
1489  * @adap: the adapter
1490  * @addr: the I2C address of the notifying device
1491  * Context: can't sleep
1492  *
1493  * Helper function to be called from an I2C bus driver's interrupt
1494  * handler. It will schedule the Host Notify IRQ.
1495  */
i2c_handle_smbus_host_notify(struct i2c_adapter * adap,unsigned short addr)1496 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1497 {
1498 	int irq;
1499 
1500 	if (!adap)
1501 		return -EINVAL;
1502 
1503 	dev_dbg(&adap->dev, "Detected HostNotify from address 0x%02x", addr);
1504 
1505 	irq = irq_find_mapping(adap->host_notify_domain, addr);
1506 	if (irq <= 0)
1507 		return -ENXIO;
1508 
1509 	generic_handle_irq_safe(irq);
1510 
1511 	return 0;
1512 }
1513 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1514 
i2c_register_adapter(struct i2c_adapter * adap)1515 static int i2c_register_adapter(struct i2c_adapter *adap)
1516 {
1517 	int res = -EINVAL;
1518 
1519 	/* Can't register until after driver model init */
1520 	if (WARN_ON(!is_registered)) {
1521 		res = -EAGAIN;
1522 		goto out_list;
1523 	}
1524 
1525 	/* Sanity checks */
1526 	if (WARN(!adap->name[0], "i2c adapter has no name"))
1527 		goto out_list;
1528 
1529 	if (!adap->algo) {
1530 		pr_err("adapter '%s': no algo supplied!\n", adap->name);
1531 		goto out_list;
1532 	}
1533 
1534 	if (!adap->lock_ops)
1535 		adap->lock_ops = &i2c_adapter_lock_ops;
1536 
1537 	adap->locked_flags = 0;
1538 	rt_mutex_init(&adap->bus_lock);
1539 	rt_mutex_init(&adap->mux_lock);
1540 	mutex_init(&adap->userspace_clients_lock);
1541 	INIT_LIST_HEAD(&adap->userspace_clients);
1542 
1543 	/* Set default timeout to 1 second if not already set */
1544 	if (adap->timeout == 0)
1545 		adap->timeout = HZ;
1546 
1547 	/* register soft irqs for Host Notify */
1548 	res = i2c_setup_host_notify_irq_domain(adap);
1549 	if (res) {
1550 		pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1551 		       adap->name, res);
1552 		goto out_list;
1553 	}
1554 
1555 	dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1556 	adap->dev.bus = &i2c_bus_type;
1557 	adap->dev.type = &i2c_adapter_type;
1558 	device_initialize(&adap->dev);
1559 
1560 	/*
1561 	 * This adapter can be used as a parent immediately after device_add(),
1562 	 * setup runtime-pm (especially ignore-children) before hand.
1563 	 */
1564 	device_enable_async_suspend(&adap->dev);
1565 	pm_runtime_no_callbacks(&adap->dev);
1566 	pm_suspend_ignore_children(&adap->dev, true);
1567 	pm_runtime_enable(&adap->dev);
1568 
1569 	res = device_add(&adap->dev);
1570 	if (res) {
1571 		pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1572 		put_device(&adap->dev);
1573 		goto out_list;
1574 	}
1575 
1576 	adap->debugfs = debugfs_create_dir(dev_name(&adap->dev), i2c_debugfs_root);
1577 
1578 	res = i2c_setup_smbus_alert(adap);
1579 	if (res)
1580 		goto out_reg;
1581 
1582 	res = i2c_init_recovery(adap);
1583 	if (res == -EPROBE_DEFER)
1584 		goto out_reg;
1585 
1586 	dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1587 
1588 	/* create pre-declared device nodes */
1589 	of_i2c_register_devices(adap);
1590 	i2c_acpi_install_space_handler(adap);
1591 	i2c_acpi_register_devices(adap);
1592 
1593 	if (adap->nr < __i2c_first_dynamic_bus_num)
1594 		i2c_scan_static_board_info(adap);
1595 
1596 	/* Notify drivers */
1597 	mutex_lock(&core_lock);
1598 	bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1599 	mutex_unlock(&core_lock);
1600 
1601 	return 0;
1602 
1603 out_reg:
1604 	debugfs_remove_recursive(adap->debugfs);
1605 	init_completion(&adap->dev_released);
1606 	device_unregister(&adap->dev);
1607 	wait_for_completion(&adap->dev_released);
1608 out_list:
1609 	mutex_lock(&core_lock);
1610 	idr_remove(&i2c_adapter_idr, adap->nr);
1611 	mutex_unlock(&core_lock);
1612 	return res;
1613 }
1614 
1615 /**
1616  * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1617  * @adap: the adapter to register (with adap->nr initialized)
1618  * Context: can sleep
1619  *
1620  * See i2c_add_numbered_adapter() for details.
1621  */
__i2c_add_numbered_adapter(struct i2c_adapter * adap)1622 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1623 {
1624 	int id;
1625 
1626 	mutex_lock(&core_lock);
1627 	id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1628 	mutex_unlock(&core_lock);
1629 	if (WARN(id < 0, "couldn't get idr"))
1630 		return id == -ENOSPC ? -EBUSY : id;
1631 
1632 	return i2c_register_adapter(adap);
1633 }
1634 
1635 /**
1636  * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1637  * @adapter: the adapter to add
1638  * Context: can sleep
1639  *
1640  * This routine is used to declare an I2C adapter when its bus number
1641  * doesn't matter or when its bus number is specified by an dt alias.
1642  * Examples of bases when the bus number doesn't matter: I2C adapters
1643  * dynamically added by USB links or PCI plugin cards.
1644  *
1645  * When this returns zero, a new bus number was allocated and stored
1646  * in adap->nr, and the specified adapter became available for clients.
1647  * Otherwise, a negative errno value is returned.
1648  */
i2c_add_adapter(struct i2c_adapter * adapter)1649 int i2c_add_adapter(struct i2c_adapter *adapter)
1650 {
1651 	struct device *dev = &adapter->dev;
1652 	int id;
1653 
1654 	if (dev->of_node) {
1655 		id = of_alias_get_id(dev->of_node, "i2c");
1656 		if (id >= 0) {
1657 			adapter->nr = id;
1658 			return __i2c_add_numbered_adapter(adapter);
1659 		}
1660 	}
1661 
1662 	mutex_lock(&core_lock);
1663 	id = idr_alloc(&i2c_adapter_idr, adapter,
1664 		       __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1665 	mutex_unlock(&core_lock);
1666 	if (WARN(id < 0, "couldn't get idr"))
1667 		return id;
1668 
1669 	adapter->nr = id;
1670 
1671 	return i2c_register_adapter(adapter);
1672 }
1673 EXPORT_SYMBOL(i2c_add_adapter);
1674 
1675 /**
1676  * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1677  * @adap: the adapter to register (with adap->nr initialized)
1678  * Context: can sleep
1679  *
1680  * This routine is used to declare an I2C adapter when its bus number
1681  * matters.  For example, use it for I2C adapters from system-on-chip CPUs,
1682  * or otherwise built in to the system's mainboard, and where i2c_board_info
1683  * is used to properly configure I2C devices.
1684  *
1685  * If the requested bus number is set to -1, then this function will behave
1686  * identically to i2c_add_adapter, and will dynamically assign a bus number.
1687  *
1688  * If no devices have pre-been declared for this bus, then be sure to
1689  * register the adapter before any dynamically allocated ones.  Otherwise
1690  * the required bus ID may not be available.
1691  *
1692  * When this returns zero, the specified adapter became available for
1693  * clients using the bus number provided in adap->nr.  Also, the table
1694  * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1695  * and the appropriate driver model device nodes are created.  Otherwise, a
1696  * negative errno value is returned.
1697  */
i2c_add_numbered_adapter(struct i2c_adapter * adap)1698 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1699 {
1700 	if (adap->nr == -1) /* -1 means dynamically assign bus id */
1701 		return i2c_add_adapter(adap);
1702 
1703 	return __i2c_add_numbered_adapter(adap);
1704 }
1705 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1706 
i2c_do_del_adapter(struct i2c_driver * driver,struct i2c_adapter * adapter)1707 static void i2c_do_del_adapter(struct i2c_driver *driver,
1708 			      struct i2c_adapter *adapter)
1709 {
1710 	struct i2c_client *client, *_n;
1711 
1712 	/* Remove the devices we created ourselves as the result of hardware
1713 	 * probing (using a driver's detect method) */
1714 	list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1715 		if (client->adapter == adapter) {
1716 			dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1717 				client->name, client->addr);
1718 			list_del(&client->detected);
1719 			i2c_unregister_device(client);
1720 		}
1721 	}
1722 }
1723 
__unregister_client(struct device * dev,void * dummy)1724 static int __unregister_client(struct device *dev, void *dummy)
1725 {
1726 	struct i2c_client *client = i2c_verify_client(dev);
1727 	if (client && strcmp(client->name, "dummy"))
1728 		i2c_unregister_device(client);
1729 	return 0;
1730 }
1731 
__unregister_dummy(struct device * dev,void * dummy)1732 static int __unregister_dummy(struct device *dev, void *dummy)
1733 {
1734 	struct i2c_client *client = i2c_verify_client(dev);
1735 	i2c_unregister_device(client);
1736 	return 0;
1737 }
1738 
__process_removed_adapter(struct device_driver * d,void * data)1739 static int __process_removed_adapter(struct device_driver *d, void *data)
1740 {
1741 	i2c_do_del_adapter(to_i2c_driver(d), data);
1742 	return 0;
1743 }
1744 
1745 /**
1746  * i2c_del_adapter - unregister I2C adapter
1747  * @adap: the adapter being unregistered
1748  * Context: can sleep
1749  *
1750  * This unregisters an I2C adapter which was previously registered
1751  * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1752  */
i2c_del_adapter(struct i2c_adapter * adap)1753 void i2c_del_adapter(struct i2c_adapter *adap)
1754 {
1755 	struct i2c_adapter *found;
1756 	struct i2c_client *client, *next;
1757 
1758 	/* First make sure that this adapter was ever added */
1759 	mutex_lock(&core_lock);
1760 	found = idr_find(&i2c_adapter_idr, adap->nr);
1761 	mutex_unlock(&core_lock);
1762 	if (found != adap) {
1763 		pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1764 		return;
1765 	}
1766 
1767 	i2c_acpi_remove_space_handler(adap);
1768 	/* Tell drivers about this removal */
1769 	mutex_lock(&core_lock);
1770 	bus_for_each_drv(&i2c_bus_type, NULL, adap,
1771 			       __process_removed_adapter);
1772 	mutex_unlock(&core_lock);
1773 
1774 	/* Remove devices instantiated from sysfs */
1775 	mutex_lock_nested(&adap->userspace_clients_lock,
1776 			  i2c_adapter_depth(adap));
1777 	list_for_each_entry_safe(client, next, &adap->userspace_clients,
1778 				 detected) {
1779 		dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1780 			client->addr);
1781 		list_del(&client->detected);
1782 		i2c_unregister_device(client);
1783 	}
1784 	mutex_unlock(&adap->userspace_clients_lock);
1785 
1786 	/* Detach any active clients. This can't fail, thus we do not
1787 	 * check the returned value. This is a two-pass process, because
1788 	 * we can't remove the dummy devices during the first pass: they
1789 	 * could have been instantiated by real devices wishing to clean
1790 	 * them up properly, so we give them a chance to do that first. */
1791 	device_for_each_child(&adap->dev, NULL, __unregister_client);
1792 	device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1793 
1794 	/* device name is gone after device_unregister */
1795 	dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1796 
1797 	pm_runtime_disable(&adap->dev);
1798 
1799 	i2c_host_notify_irq_teardown(adap);
1800 
1801 	debugfs_remove_recursive(adap->debugfs);
1802 
1803 	/* wait until all references to the device are gone
1804 	 *
1805 	 * FIXME: This is old code and should ideally be replaced by an
1806 	 * alternative which results in decoupling the lifetime of the struct
1807 	 * device from the i2c_adapter, like spi or netdev do. Any solution
1808 	 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1809 	 */
1810 	init_completion(&adap->dev_released);
1811 	device_unregister(&adap->dev);
1812 	wait_for_completion(&adap->dev_released);
1813 
1814 	/* free bus id */
1815 	mutex_lock(&core_lock);
1816 	idr_remove(&i2c_adapter_idr, adap->nr);
1817 	mutex_unlock(&core_lock);
1818 
1819 	/* Clear the device structure in case this adapter is ever going to be
1820 	   added again */
1821 	memset(&adap->dev, 0, sizeof(adap->dev));
1822 }
1823 EXPORT_SYMBOL(i2c_del_adapter);
1824 
devm_i2c_del_adapter(void * adapter)1825 static void devm_i2c_del_adapter(void *adapter)
1826 {
1827 	i2c_del_adapter(adapter);
1828 }
1829 
1830 /**
1831  * devm_i2c_add_adapter - device-managed variant of i2c_add_adapter()
1832  * @dev: managing device for adding this I2C adapter
1833  * @adapter: the adapter to add
1834  * Context: can sleep
1835  *
1836  * Add adapter with dynamic bus number, same with i2c_add_adapter()
1837  * but the adapter will be auto deleted on driver detach.
1838  */
devm_i2c_add_adapter(struct device * dev,struct i2c_adapter * adapter)1839 int devm_i2c_add_adapter(struct device *dev, struct i2c_adapter *adapter)
1840 {
1841 	int ret;
1842 
1843 	ret = i2c_add_adapter(adapter);
1844 	if (ret)
1845 		return ret;
1846 
1847 	return devm_add_action_or_reset(dev, devm_i2c_del_adapter, adapter);
1848 }
1849 EXPORT_SYMBOL_GPL(devm_i2c_add_adapter);
1850 
i2c_dev_or_parent_fwnode_match(struct device * dev,const void * data)1851 static int i2c_dev_or_parent_fwnode_match(struct device *dev, const void *data)
1852 {
1853 	if (dev_fwnode(dev) == data)
1854 		return 1;
1855 
1856 	if (dev->parent && dev_fwnode(dev->parent) == data)
1857 		return 1;
1858 
1859 	return 0;
1860 }
1861 
1862 /**
1863  * i2c_find_adapter_by_fwnode() - find an i2c_adapter for the fwnode
1864  * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_adapter
1865  *
1866  * Look up and return the &struct i2c_adapter corresponding to the @fwnode.
1867  * If no adapter can be found, or @fwnode is NULL, this returns NULL.
1868  *
1869  * The user must call put_device(&adapter->dev) once done with the i2c adapter.
1870  */
i2c_find_adapter_by_fwnode(struct fwnode_handle * fwnode)1871 struct i2c_adapter *i2c_find_adapter_by_fwnode(struct fwnode_handle *fwnode)
1872 {
1873 	struct i2c_adapter *adapter;
1874 	struct device *dev;
1875 
1876 	if (!fwnode)
1877 		return NULL;
1878 
1879 	dev = bus_find_device(&i2c_bus_type, NULL, fwnode,
1880 			      i2c_dev_or_parent_fwnode_match);
1881 	if (!dev)
1882 		return NULL;
1883 
1884 	adapter = i2c_verify_adapter(dev);
1885 	if (!adapter)
1886 		put_device(dev);
1887 
1888 	return adapter;
1889 }
1890 EXPORT_SYMBOL(i2c_find_adapter_by_fwnode);
1891 
1892 /**
1893  * i2c_get_adapter_by_fwnode() - find an i2c_adapter for the fwnode
1894  * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_adapter
1895  *
1896  * Look up and return the &struct i2c_adapter corresponding to the @fwnode,
1897  * and increment the adapter module's use count. If no adapter can be found,
1898  * or @fwnode is NULL, this returns NULL.
1899  *
1900  * The user must call i2c_put_adapter(adapter) once done with the i2c adapter.
1901  * Note that this is different from i2c_find_adapter_by_node().
1902  */
i2c_get_adapter_by_fwnode(struct fwnode_handle * fwnode)1903 struct i2c_adapter *i2c_get_adapter_by_fwnode(struct fwnode_handle *fwnode)
1904 {
1905 	struct i2c_adapter *adapter;
1906 
1907 	adapter = i2c_find_adapter_by_fwnode(fwnode);
1908 	if (!adapter)
1909 		return NULL;
1910 
1911 	if (!try_module_get(adapter->owner)) {
1912 		put_device(&adapter->dev);
1913 		adapter = NULL;
1914 	}
1915 
1916 	return adapter;
1917 }
1918 EXPORT_SYMBOL(i2c_get_adapter_by_fwnode);
1919 
i2c_parse_timing(struct device * dev,char * prop_name,u32 * cur_val_p,u32 def_val,bool use_def)1920 static void i2c_parse_timing(struct device *dev, char *prop_name, u32 *cur_val_p,
1921 			    u32 def_val, bool use_def)
1922 {
1923 	int ret;
1924 
1925 	ret = device_property_read_u32(dev, prop_name, cur_val_p);
1926 	if (ret && use_def)
1927 		*cur_val_p = def_val;
1928 
1929 	dev_dbg(dev, "%s: %u\n", prop_name, *cur_val_p);
1930 }
1931 
1932 /**
1933  * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1934  * @dev: The device to scan for I2C timing properties
1935  * @t: the i2c_timings struct to be filled with values
1936  * @use_defaults: bool to use sane defaults derived from the I2C specification
1937  *		  when properties are not found, otherwise don't update
1938  *
1939  * Scan the device for the generic I2C properties describing timing parameters
1940  * for the signal and fill the given struct with the results. If a property was
1941  * not found and use_defaults was true, then maximum timings are assumed which
1942  * are derived from the I2C specification. If use_defaults is not used, the
1943  * results will be as before, so drivers can apply their own defaults before
1944  * calling this helper. The latter is mainly intended for avoiding regressions
1945  * of existing drivers which want to switch to this function. New drivers
1946  * almost always should use the defaults.
1947  */
i2c_parse_fw_timings(struct device * dev,struct i2c_timings * t,bool use_defaults)1948 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1949 {
1950 	bool u = use_defaults;
1951 	u32 d;
1952 
1953 	i2c_parse_timing(dev, "clock-frequency", &t->bus_freq_hz,
1954 			 I2C_MAX_STANDARD_MODE_FREQ, u);
1955 
1956 	d = t->bus_freq_hz <= I2C_MAX_STANDARD_MODE_FREQ ? 1000 :
1957 	    t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120;
1958 	i2c_parse_timing(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns, d, u);
1959 
1960 	d = t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120;
1961 	i2c_parse_timing(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns, d, u);
1962 
1963 	i2c_parse_timing(dev, "i2c-scl-internal-delay-ns",
1964 			 &t->scl_int_delay_ns, 0, u);
1965 	i2c_parse_timing(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns,
1966 			 t->scl_fall_ns, u);
1967 	i2c_parse_timing(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns, 0, u);
1968 	i2c_parse_timing(dev, "i2c-digital-filter-width-ns",
1969 			 &t->digital_filter_width_ns, 0, u);
1970 	i2c_parse_timing(dev, "i2c-analog-filter-cutoff-frequency",
1971 			 &t->analog_filter_cutoff_freq_hz, 0, u);
1972 }
1973 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1974 
1975 /* ------------------------------------------------------------------------- */
1976 
i2c_for_each_dev(void * data,int (* fn)(struct device * dev,void * data))1977 int i2c_for_each_dev(void *data, int (*fn)(struct device *dev, void *data))
1978 {
1979 	int res;
1980 
1981 	mutex_lock(&core_lock);
1982 	res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1983 	mutex_unlock(&core_lock);
1984 
1985 	return res;
1986 }
1987 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1988 
__process_new_driver(struct device * dev,void * data)1989 static int __process_new_driver(struct device *dev, void *data)
1990 {
1991 	if (dev->type != &i2c_adapter_type)
1992 		return 0;
1993 	return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1994 }
1995 
1996 /*
1997  * An i2c_driver is used with one or more i2c_client (device) nodes to access
1998  * i2c slave chips, on a bus instance associated with some i2c_adapter.
1999  */
2000 
i2c_register_driver(struct module * owner,struct i2c_driver * driver)2001 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
2002 {
2003 	int res;
2004 
2005 	/* Can't register until after driver model init */
2006 	if (WARN_ON(!is_registered))
2007 		return -EAGAIN;
2008 
2009 	/* add the driver to the list of i2c drivers in the driver core */
2010 	driver->driver.owner = owner;
2011 	driver->driver.bus = &i2c_bus_type;
2012 	INIT_LIST_HEAD(&driver->clients);
2013 
2014 	/* When registration returns, the driver core
2015 	 * will have called probe() for all matching-but-unbound devices.
2016 	 */
2017 	res = driver_register(&driver->driver);
2018 	if (res)
2019 		return res;
2020 
2021 	pr_debug("driver [%s] registered\n", driver->driver.name);
2022 
2023 	/* Walk the adapters that are already present */
2024 	i2c_for_each_dev(driver, __process_new_driver);
2025 
2026 	return 0;
2027 }
2028 EXPORT_SYMBOL(i2c_register_driver);
2029 
__process_removed_driver(struct device * dev,void * data)2030 static int __process_removed_driver(struct device *dev, void *data)
2031 {
2032 	if (dev->type == &i2c_adapter_type)
2033 		i2c_do_del_adapter(data, to_i2c_adapter(dev));
2034 	return 0;
2035 }
2036 
2037 /**
2038  * i2c_del_driver - unregister I2C driver
2039  * @driver: the driver being unregistered
2040  * Context: can sleep
2041  */
i2c_del_driver(struct i2c_driver * driver)2042 void i2c_del_driver(struct i2c_driver *driver)
2043 {
2044 	i2c_for_each_dev(driver, __process_removed_driver);
2045 
2046 	driver_unregister(&driver->driver);
2047 	pr_debug("driver [%s] unregistered\n", driver->driver.name);
2048 }
2049 EXPORT_SYMBOL(i2c_del_driver);
2050 
2051 /* ------------------------------------------------------------------------- */
2052 
2053 struct i2c_cmd_arg {
2054 	unsigned	cmd;
2055 	void		*arg;
2056 };
2057 
i2c_cmd(struct device * dev,void * _arg)2058 static int i2c_cmd(struct device *dev, void *_arg)
2059 {
2060 	struct i2c_client	*client = i2c_verify_client(dev);
2061 	struct i2c_cmd_arg	*arg = _arg;
2062 	struct i2c_driver	*driver;
2063 
2064 	if (!client || !client->dev.driver)
2065 		return 0;
2066 
2067 	driver = to_i2c_driver(client->dev.driver);
2068 	if (driver->command)
2069 		driver->command(client, arg->cmd, arg->arg);
2070 	return 0;
2071 }
2072 
i2c_clients_command(struct i2c_adapter * adap,unsigned int cmd,void * arg)2073 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
2074 {
2075 	struct i2c_cmd_arg	cmd_arg;
2076 
2077 	cmd_arg.cmd = cmd;
2078 	cmd_arg.arg = arg;
2079 	device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
2080 }
2081 EXPORT_SYMBOL(i2c_clients_command);
2082 
i2c_init(void)2083 static int __init i2c_init(void)
2084 {
2085 	int retval;
2086 
2087 	retval = of_alias_get_highest_id("i2c");
2088 
2089 	down_write(&__i2c_board_lock);
2090 	if (retval >= __i2c_first_dynamic_bus_num)
2091 		__i2c_first_dynamic_bus_num = retval + 1;
2092 	up_write(&__i2c_board_lock);
2093 
2094 	retval = bus_register(&i2c_bus_type);
2095 	if (retval)
2096 		return retval;
2097 
2098 	is_registered = true;
2099 
2100 	i2c_debugfs_root = debugfs_create_dir("i2c", NULL);
2101 
2102 	retval = i2c_add_driver(&dummy_driver);
2103 	if (retval)
2104 		goto class_err;
2105 
2106 	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2107 		WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
2108 	if (IS_ENABLED(CONFIG_ACPI))
2109 		WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
2110 
2111 	return 0;
2112 
2113 class_err:
2114 	is_registered = false;
2115 	bus_unregister(&i2c_bus_type);
2116 	return retval;
2117 }
2118 
i2c_exit(void)2119 static void __exit i2c_exit(void)
2120 {
2121 	if (IS_ENABLED(CONFIG_ACPI))
2122 		WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
2123 	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2124 		WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
2125 	i2c_del_driver(&dummy_driver);
2126 	debugfs_remove_recursive(i2c_debugfs_root);
2127 	bus_unregister(&i2c_bus_type);
2128 	tracepoint_synchronize_unregister();
2129 }
2130 
2131 /* We must initialize early, because some subsystems register i2c drivers
2132  * in subsys_initcall() code, but are linked (and initialized) before i2c.
2133  */
2134 postcore_initcall(i2c_init);
2135 module_exit(i2c_exit);
2136 
2137 /* ----------------------------------------------------
2138  * the functional interface to the i2c busses.
2139  * ----------------------------------------------------
2140  */
2141 
2142 /* Check if val is exceeding the quirk IFF quirk is non 0 */
2143 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
2144 
i2c_quirk_error(struct i2c_adapter * adap,struct i2c_msg * msg,char * err_msg)2145 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
2146 {
2147 	dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
2148 			    err_msg, msg->addr, msg->len,
2149 			    msg->flags & I2C_M_RD ? "read" : "write");
2150 	return -EOPNOTSUPP;
2151 }
2152 
i2c_check_for_quirks(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)2153 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2154 {
2155 	const struct i2c_adapter_quirks *q = adap->quirks;
2156 	int max_num = q->max_num_msgs, i;
2157 	bool do_len_check = true;
2158 
2159 	if (q->flags & I2C_AQ_COMB) {
2160 		max_num = 2;
2161 
2162 		/* special checks for combined messages */
2163 		if (num == 2) {
2164 			if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
2165 				return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
2166 
2167 			if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
2168 				return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
2169 
2170 			if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
2171 				return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
2172 
2173 			if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
2174 				return i2c_quirk_error(adap, &msgs[0], "msg too long");
2175 
2176 			if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
2177 				return i2c_quirk_error(adap, &msgs[1], "msg too long");
2178 
2179 			do_len_check = false;
2180 		}
2181 	}
2182 
2183 	if (i2c_quirk_exceeded(num, max_num))
2184 		return i2c_quirk_error(adap, &msgs[0], "too many messages");
2185 
2186 	for (i = 0; i < num; i++) {
2187 		u16 len = msgs[i].len;
2188 
2189 		if (msgs[i].flags & I2C_M_RD) {
2190 			if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
2191 				return i2c_quirk_error(adap, &msgs[i], "msg too long");
2192 
2193 			if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0)
2194 				return i2c_quirk_error(adap, &msgs[i], "no zero length");
2195 		} else {
2196 			if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
2197 				return i2c_quirk_error(adap, &msgs[i], "msg too long");
2198 
2199 			if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0)
2200 				return i2c_quirk_error(adap, &msgs[i], "no zero length");
2201 		}
2202 	}
2203 
2204 	return 0;
2205 }
2206 
2207 /**
2208  * __i2c_transfer - unlocked flavor of i2c_transfer
2209  * @adap: Handle to I2C bus
2210  * @msgs: One or more messages to execute before STOP is issued to
2211  *	terminate the operation; each message begins with a START.
2212  * @num: Number of messages to be executed.
2213  *
2214  * Returns negative errno, else the number of messages executed.
2215  *
2216  * Adapter lock must be held when calling this function. No debug logging
2217  * takes place.
2218  */
__i2c_transfer(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)2219 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2220 {
2221 	unsigned long orig_jiffies;
2222 	int ret, try;
2223 
2224 	if (!adap->algo->master_xfer) {
2225 		dev_dbg(&adap->dev, "I2C level transfers not supported\n");
2226 		return -EOPNOTSUPP;
2227 	}
2228 
2229 	if (WARN_ON(!msgs || num < 1))
2230 		return -EINVAL;
2231 
2232 	ret = __i2c_check_suspended(adap);
2233 	if (ret)
2234 		return ret;
2235 
2236 	if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
2237 		return -EOPNOTSUPP;
2238 
2239 	/*
2240 	 * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
2241 	 * enabled.  This is an efficient way of keeping the for-loop from
2242 	 * being executed when not needed.
2243 	 */
2244 	if (static_branch_unlikely(&i2c_trace_msg_key)) {
2245 		int i;
2246 		for (i = 0; i < num; i++)
2247 			if (msgs[i].flags & I2C_M_RD)
2248 				trace_i2c_read(adap, &msgs[i], i);
2249 			else
2250 				trace_i2c_write(adap, &msgs[i], i);
2251 	}
2252 
2253 	/* Retry automatically on arbitration loss */
2254 	orig_jiffies = jiffies;
2255 	for (ret = 0, try = 0; try <= adap->retries; try++) {
2256 		if (i2c_in_atomic_xfer_mode() && adap->algo->master_xfer_atomic)
2257 			ret = adap->algo->master_xfer_atomic(adap, msgs, num);
2258 		else
2259 			ret = adap->algo->master_xfer(adap, msgs, num);
2260 
2261 		if (ret != -EAGAIN)
2262 			break;
2263 		if (time_after(jiffies, orig_jiffies + adap->timeout))
2264 			break;
2265 	}
2266 
2267 	if (static_branch_unlikely(&i2c_trace_msg_key)) {
2268 		int i;
2269 		for (i = 0; i < ret; i++)
2270 			if (msgs[i].flags & I2C_M_RD)
2271 				trace_i2c_reply(adap, &msgs[i], i);
2272 		trace_i2c_result(adap, num, ret);
2273 	}
2274 
2275 	return ret;
2276 }
2277 EXPORT_SYMBOL(__i2c_transfer);
2278 
2279 /**
2280  * i2c_transfer - execute a single or combined I2C message
2281  * @adap: Handle to I2C bus
2282  * @msgs: One or more messages to execute before STOP is issued to
2283  *	terminate the operation; each message begins with a START.
2284  * @num: Number of messages to be executed.
2285  *
2286  * Returns negative errno, else the number of messages executed.
2287  *
2288  * Note that there is no requirement that each message be sent to
2289  * the same slave address, although that is the most common model.
2290  */
i2c_transfer(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)2291 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2292 {
2293 	int ret;
2294 
2295 	/* REVISIT the fault reporting model here is weak:
2296 	 *
2297 	 *  - When we get an error after receiving N bytes from a slave,
2298 	 *    there is no way to report "N".
2299 	 *
2300 	 *  - When we get a NAK after transmitting N bytes to a slave,
2301 	 *    there is no way to report "N" ... or to let the master
2302 	 *    continue executing the rest of this combined message, if
2303 	 *    that's the appropriate response.
2304 	 *
2305 	 *  - When for example "num" is two and we successfully complete
2306 	 *    the first message but get an error part way through the
2307 	 *    second, it's unclear whether that should be reported as
2308 	 *    one (discarding status on the second message) or errno
2309 	 *    (discarding status on the first one).
2310 	 */
2311 	ret = __i2c_lock_bus_helper(adap);
2312 	if (ret)
2313 		return ret;
2314 
2315 	ret = __i2c_transfer(adap, msgs, num);
2316 	i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
2317 
2318 	return ret;
2319 }
2320 EXPORT_SYMBOL(i2c_transfer);
2321 
2322 /**
2323  * i2c_transfer_buffer_flags - issue a single I2C message transferring data
2324  *			       to/from a buffer
2325  * @client: Handle to slave device
2326  * @buf: Where the data is stored
2327  * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
2328  * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
2329  *
2330  * Returns negative errno, or else the number of bytes transferred.
2331  */
i2c_transfer_buffer_flags(const struct i2c_client * client,char * buf,int count,u16 flags)2332 int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
2333 			      int count, u16 flags)
2334 {
2335 	int ret;
2336 	struct i2c_msg msg = {
2337 		.addr = client->addr,
2338 		.flags = flags | (client->flags & I2C_M_TEN),
2339 		.len = count,
2340 		.buf = buf,
2341 	};
2342 
2343 	ret = i2c_transfer(client->adapter, &msg, 1);
2344 
2345 	/*
2346 	 * If everything went ok (i.e. 1 msg transferred), return #bytes
2347 	 * transferred, else error code.
2348 	 */
2349 	return (ret == 1) ? count : ret;
2350 }
2351 EXPORT_SYMBOL(i2c_transfer_buffer_flags);
2352 
2353 /**
2354  * i2c_get_device_id - get manufacturer, part id and die revision of a device
2355  * @client: The device to query
2356  * @id: The queried information
2357  *
2358  * Returns negative errno on error, zero on success.
2359  */
i2c_get_device_id(const struct i2c_client * client,struct i2c_device_identity * id)2360 int i2c_get_device_id(const struct i2c_client *client,
2361 		      struct i2c_device_identity *id)
2362 {
2363 	struct i2c_adapter *adap = client->adapter;
2364 	union i2c_smbus_data raw_id;
2365 	int ret;
2366 
2367 	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
2368 		return -EOPNOTSUPP;
2369 
2370 	raw_id.block[0] = 3;
2371 	ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0,
2372 			     I2C_SMBUS_READ, client->addr << 1,
2373 			     I2C_SMBUS_I2C_BLOCK_DATA, &raw_id);
2374 	if (ret)
2375 		return ret;
2376 
2377 	id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
2378 	id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
2379 	id->die_revision = raw_id.block[3] & 0x7;
2380 	return 0;
2381 }
2382 EXPORT_SYMBOL_GPL(i2c_get_device_id);
2383 
2384 /**
2385  * i2c_client_get_device_id - get the driver match table entry of a device
2386  * @client: the device to query. The device must be bound to a driver
2387  *
2388  * Returns a pointer to the matching entry if found, NULL otherwise.
2389  */
i2c_client_get_device_id(const struct i2c_client * client)2390 const struct i2c_device_id *i2c_client_get_device_id(const struct i2c_client *client)
2391 {
2392 	const struct i2c_driver *drv = to_i2c_driver(client->dev.driver);
2393 
2394 	return i2c_match_id(drv->id_table, client);
2395 }
2396 EXPORT_SYMBOL_GPL(i2c_client_get_device_id);
2397 
2398 /* ----------------------------------------------------
2399  * the i2c address scanning function
2400  * Will not work for 10-bit addresses!
2401  * ----------------------------------------------------
2402  */
2403 
2404 /*
2405  * Legacy default probe function, mostly relevant for SMBus. The default
2406  * probe method is a quick write, but it is known to corrupt the 24RF08
2407  * EEPROMs due to a state machine bug, and could also irreversibly
2408  * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2409  * we use a short byte read instead. Also, some bus drivers don't implement
2410  * quick write, so we fallback to a byte read in that case too.
2411  * On x86, there is another special case for FSC hardware monitoring chips,
2412  * which want regular byte reads (address 0x73.) Fortunately, these are the
2413  * only known chips using this I2C address on PC hardware.
2414  * Returns 1 if probe succeeded, 0 if not.
2415  */
i2c_default_probe(struct i2c_adapter * adap,unsigned short addr)2416 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2417 {
2418 	int err;
2419 	union i2c_smbus_data dummy;
2420 
2421 #ifdef CONFIG_X86
2422 	if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2423 	 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2424 		err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2425 				     I2C_SMBUS_BYTE_DATA, &dummy);
2426 	else
2427 #endif
2428 	if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2429 	 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2430 		err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2431 				     I2C_SMBUS_QUICK, NULL);
2432 	else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2433 		err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2434 				     I2C_SMBUS_BYTE, &dummy);
2435 	else {
2436 		dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2437 			 addr);
2438 		err = -EOPNOTSUPP;
2439 	}
2440 
2441 	return err >= 0;
2442 }
2443 
i2c_detect_address(struct i2c_client * temp_client,struct i2c_driver * driver)2444 static int i2c_detect_address(struct i2c_client *temp_client,
2445 			      struct i2c_driver *driver)
2446 {
2447 	struct i2c_board_info info;
2448 	struct i2c_adapter *adapter = temp_client->adapter;
2449 	int addr = temp_client->addr;
2450 	int err;
2451 
2452 	/* Make sure the address is valid */
2453 	err = i2c_check_7bit_addr_validity_strict(addr);
2454 	if (err) {
2455 		dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2456 			 addr);
2457 		return err;
2458 	}
2459 
2460 	/* Skip if already in use (7 bit, no need to encode flags) */
2461 	if (i2c_check_addr_busy(adapter, addr))
2462 		return 0;
2463 
2464 	/* Make sure there is something at this address */
2465 	if (!i2c_default_probe(adapter, addr))
2466 		return 0;
2467 
2468 	/* Finally call the custom detection function */
2469 	memset(&info, 0, sizeof(struct i2c_board_info));
2470 	info.addr = addr;
2471 	err = driver->detect(temp_client, &info);
2472 	if (err) {
2473 		/* -ENODEV is returned if the detection fails. We catch it
2474 		   here as this isn't an error. */
2475 		return err == -ENODEV ? 0 : err;
2476 	}
2477 
2478 	/* Consistency check */
2479 	if (info.type[0] == '\0') {
2480 		dev_err(&adapter->dev,
2481 			"%s detection function provided no name for 0x%x\n",
2482 			driver->driver.name, addr);
2483 	} else {
2484 		struct i2c_client *client;
2485 
2486 		/* Detection succeeded, instantiate the device */
2487 		if (adapter->class & I2C_CLASS_DEPRECATED)
2488 			dev_warn(&adapter->dev,
2489 				"This adapter will soon drop class based instantiation of devices. "
2490 				"Please make sure client 0x%02x gets instantiated by other means. "
2491 				"Check 'Documentation/i2c/instantiating-devices.rst' for details.\n",
2492 				info.addr);
2493 
2494 		dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2495 			info.type, info.addr);
2496 		client = i2c_new_client_device(adapter, &info);
2497 		if (!IS_ERR(client))
2498 			list_add_tail(&client->detected, &driver->clients);
2499 		else
2500 			dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2501 				info.type, info.addr);
2502 	}
2503 	return 0;
2504 }
2505 
i2c_detect(struct i2c_adapter * adapter,struct i2c_driver * driver)2506 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2507 {
2508 	const unsigned short *address_list;
2509 	struct i2c_client *temp_client;
2510 	int i, err = 0;
2511 
2512 	address_list = driver->address_list;
2513 	if (!driver->detect || !address_list)
2514 		return 0;
2515 
2516 	/* Warn that the adapter lost class based instantiation */
2517 	if (adapter->class == I2C_CLASS_DEPRECATED) {
2518 		dev_dbg(&adapter->dev,
2519 			"This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2520 			"If you need it, check 'Documentation/i2c/instantiating-devices.rst' for alternatives.\n",
2521 			driver->driver.name);
2522 		return 0;
2523 	}
2524 
2525 	/* Stop here if the classes do not match */
2526 	if (!(adapter->class & driver->class))
2527 		return 0;
2528 
2529 	/* Set up a temporary client to help detect callback */
2530 	temp_client = kzalloc(sizeof(*temp_client), GFP_KERNEL);
2531 	if (!temp_client)
2532 		return -ENOMEM;
2533 
2534 	temp_client->adapter = adapter;
2535 
2536 	for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2537 		dev_dbg(&adapter->dev,
2538 			"found normal entry for adapter %d, addr 0x%02x\n",
2539 			i2c_adapter_id(adapter), address_list[i]);
2540 		temp_client->addr = address_list[i];
2541 		err = i2c_detect_address(temp_client, driver);
2542 		if (unlikely(err))
2543 			break;
2544 	}
2545 
2546 	kfree(temp_client);
2547 
2548 	return err;
2549 }
2550 
i2c_probe_func_quick_read(struct i2c_adapter * adap,unsigned short addr)2551 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2552 {
2553 	return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2554 			      I2C_SMBUS_QUICK, NULL) >= 0;
2555 }
2556 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2557 
2558 struct i2c_client *
i2c_new_scanned_device(struct i2c_adapter * adap,struct i2c_board_info * info,unsigned short const * addr_list,int (* probe)(struct i2c_adapter * adap,unsigned short addr))2559 i2c_new_scanned_device(struct i2c_adapter *adap,
2560 		       struct i2c_board_info *info,
2561 		       unsigned short const *addr_list,
2562 		       int (*probe)(struct i2c_adapter *adap, unsigned short addr))
2563 {
2564 	int i;
2565 
2566 	if (!probe)
2567 		probe = i2c_default_probe;
2568 
2569 	for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2570 		/* Check address validity */
2571 		if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2572 			dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2573 				 addr_list[i]);
2574 			continue;
2575 		}
2576 
2577 		/* Check address availability (7 bit, no need to encode flags) */
2578 		if (i2c_check_addr_busy(adap, addr_list[i])) {
2579 			dev_dbg(&adap->dev,
2580 				"Address 0x%02x already in use, not probing\n",
2581 				addr_list[i]);
2582 			continue;
2583 		}
2584 
2585 		/* Test address responsiveness */
2586 		if (probe(adap, addr_list[i]))
2587 			break;
2588 	}
2589 
2590 	if (addr_list[i] == I2C_CLIENT_END) {
2591 		dev_dbg(&adap->dev, "Probing failed, no device found\n");
2592 		return ERR_PTR(-ENODEV);
2593 	}
2594 
2595 	info->addr = addr_list[i];
2596 	return i2c_new_client_device(adap, info);
2597 }
2598 EXPORT_SYMBOL_GPL(i2c_new_scanned_device);
2599 
i2c_get_adapter(int nr)2600 struct i2c_adapter *i2c_get_adapter(int nr)
2601 {
2602 	struct i2c_adapter *adapter;
2603 
2604 	mutex_lock(&core_lock);
2605 	adapter = idr_find(&i2c_adapter_idr, nr);
2606 	if (!adapter)
2607 		goto exit;
2608 
2609 	if (try_module_get(adapter->owner))
2610 		get_device(&adapter->dev);
2611 	else
2612 		adapter = NULL;
2613 
2614  exit:
2615 	mutex_unlock(&core_lock);
2616 	return adapter;
2617 }
2618 EXPORT_SYMBOL(i2c_get_adapter);
2619 
i2c_put_adapter(struct i2c_adapter * adap)2620 void i2c_put_adapter(struct i2c_adapter *adap)
2621 {
2622 	if (!adap)
2623 		return;
2624 
2625 	module_put(adap->owner);
2626 	/* Should be last, otherwise we risk use-after-free with 'adap' */
2627 	put_device(&adap->dev);
2628 }
2629 EXPORT_SYMBOL(i2c_put_adapter);
2630 
2631 /**
2632  * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2633  * @msg: the message to be checked
2634  * @threshold: the minimum number of bytes for which using DMA makes sense.
2635  *	       Should at least be 1.
2636  *
2637  * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
2638  *	   Or a valid pointer to be used with DMA. After use, release it by
2639  *	   calling i2c_put_dma_safe_msg_buf().
2640  *
2641  * This function must only be called from process context!
2642  */
i2c_get_dma_safe_msg_buf(struct i2c_msg * msg,unsigned int threshold)2643 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
2644 {
2645 	/* also skip 0-length msgs for bogus thresholds of 0 */
2646 	if (!threshold)
2647 		pr_debug("DMA buffer for addr=0x%02x with length 0 is bogus\n",
2648 			 msg->addr);
2649 	if (msg->len < threshold || msg->len == 0)
2650 		return NULL;
2651 
2652 	if (msg->flags & I2C_M_DMA_SAFE)
2653 		return msg->buf;
2654 
2655 	pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2656 		 msg->addr, msg->len);
2657 
2658 	if (msg->flags & I2C_M_RD)
2659 		return kzalloc(msg->len, GFP_KERNEL);
2660 	else
2661 		return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2662 }
2663 EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2664 
2665 /**
2666  * i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2667  * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2668  * @msg: the message which the buffer corresponds to
2669  * @xferred: bool saying if the message was transferred
2670  */
i2c_put_dma_safe_msg_buf(u8 * buf,struct i2c_msg * msg,bool xferred)2671 void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred)
2672 {
2673 	if (!buf || buf == msg->buf)
2674 		return;
2675 
2676 	if (xferred && msg->flags & I2C_M_RD)
2677 		memcpy(msg->buf, buf, msg->len);
2678 
2679 	kfree(buf);
2680 }
2681 EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf);
2682 
2683 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2684 MODULE_DESCRIPTION("I2C-Bus main module");
2685 MODULE_LICENSE("GPL");
2686